A tetrose is a monosaccharide with 4 carbon atoms. They have either an aldehyde functional group in position 1 (aldotetroses) or a ketone functional group in position 2 (ketotetroses). File:DErythrose Fischer.svg | D-Erythrose File:DThreose Fischer.svg | D-Threose File:DErythrulose Fischer.svg | D-Erythrulose The aldotetroses have two chiral cente... Found on http://en.wikipedia.org/wiki/Tetrose